Conventionally, various types of holders capable of being adjusted in six axes have been proposed for optical elements such as charge coupled devices (CCDs) and liquid crystal devices (LCDs). For example, a holder shown in FIG. 1 comprising stages 1, 2, 3 and 4 may be adjusted in directions X, Y, Z and .theta., respectively, wherein the stages are assembled so that they are superposed one on top of another. As to directions .theta.1 and .theta.2, adjustment is made by fixing the holder while tilting it in directions .theta.1 and .theta.2 (see, for example, Japanese Laid-open Patent Application No. H8-95013).
In a holder shown in FIG. 2, a stage 8 is made movable in directions X and .theta. through levers 7a and 7b by forward and backward movements of two adjustment screws 6a and 6b, thereby reducing the number of stages. However, since the center of rotation for the .theta.-direction adjustment disaccords with the center of the optical element, it is necessary to perform re-adjustment in the X and Y directions after the .theta.-direction adjustment is performed (see, for example, Japanese Published Utility Model Application No. H6-17156).
In any case, the conventional optical element holders capable of being adjusted in six axes generally have complicated structures and a large number of parts.